1. Ch. 18 Renewable resources!!

2. Renewable energy – energy from sources that are constantly being formed
Solar - sun
Hydroelectric – moving water
Wind
Biomass – organic material
Geothermal – Earth’s heat
Tidal - waves

3. Solar Energy - energy from the sun
Nuclear Fusion creates energy on the sun
Only a fraction of this reached the Earth
But, this is enough to power:
The wind (wind power)
Plant growth (biomass)
The water cycle (hydroelectricity)
Nearly all renewable energy sources come from the sun!!!

4. Passive Solar – using the sun to heat something directly (ex: through windows)

5. Active Solar – collecting the suns energy to heat buildings or water (ex: solar cells or panels)
Energy production from solar has doubled every 4 years since 1985!!

6. Costs of Solar Energy
All costs are up front costs, then savings follow
Solar pool heater - $ $4000
Home solar water heater $ $3500
(includes installation)
1 kW power system $10,000 – $15,000
2 kW power system $16,000 - $20,000
5 kW power system $35,000 - $45,000
(will power most homes)
You can get federal tax credits up to $2000 and some state tax credits as well

7. Wind Power
Heat from the sun does not warm the earth evenly, causing the flow of air masses = wind
Fastest growing energy source
Cost is decreasing

8. Wind Farms
Farmers can sell excess energy back to their local utility!!
The windiest places on Earth could generate 10 times more energy needed on earth!!
Problem: Transporting the energy from rural areas to where it is needed

9. Biomass Power - any organic matter that is used as an energy source
Plants material, manure, methane, alcohol
Major source of energy in developing countries!
Problems:
cutting too many trees can cause severe environmental problems
Burning can release large amounts of air pollution

10. Methane – a byproduct of decomposition
Britain’s first Dung-Fired Power plant using the methane released from cow manure for energy
US uses some energy from methane produced from landfills!

11. Ethanol Produced from biomass! Benefits: Cons: Renewable
Less emissions
Cons:
Takes lots of land
Rise in produce prices

12. Hydroelectricity – energy produced by moving water
20% of the worlds electricity
Leading Countries
Canada US
Brazil
China
Russia
Norway

13. Hydroelectric Energy Benefits Disadvantages Inexpensive to operate
No air pollution
Last longer than fossil fuel plants
Flood control
recreation
Disadvantages
Changes a rivers flow
Reservoir floods the area
Displaces people
Reduces water flow
Destroys salmon fisheries
Dam failure
Sedimentation
Today: the era of large dam construction is most likely over
We are now using micro-hydropower

14. Geothermal Energy – energy from heat in the earth’s crust
US is the worlds largest producer of geothermal energy

15. Costs of Geothermal Heat Pumps
Drilling/installation = $10,000 - $25,000
You can get federal tax credits up to $2000 and some state tax credits

16. Alternative Energy – energy sources that are still in development
How to get off the alternative list?
Prove it is cost effective
Environmental effects must be acceptable
Current Alternative energy sources
Tidal Power Ocean
Ocean Thermal Energy Conversion (OTEC)
Hydrogen

17. Tidal Power
Tides – the movement of water caused by gravitational attractions between the sun, Earth and the moon.
Currently used in
France
Russia
Canada
Cost is high and
not many places
suitable enough

18. Ocean Thermal Energy Conversion
Warm ocean surface temperatures and cold subsurface temperatures are used to create electricity
Surface temps boil water making steam….
Cold subsurface water cools the steam
Problems
Pumping water costs too much
Pumping cold water to the surface could cause problems

19. Hydrogen?? The most abundant element in the universe!
Burning it produces water vapor – not pollution
Electricity is used to split water molecules to get hydrogen gas
Challenges:
Takes a lot of energy to make
Not safe to store

20. Fuel Cells
Combining Hydrogen and Oxygen produces electricity and its byproduct is water!
No Emissions!!

21. Energy Efficiency - % of energy put into a system that does useful work
Ex: a light bulbs light output not its heat energy
More than 40% of energy produced in the US is wasted!!
How to improve
Public transport
More efficient engines, i.e. fuel cells

22. Hybrid Cars Less emissions Small efficient gas engine Electric motor
Convert breaking energy into electricity
Aerodynamic
Lightweight material

23. Cogeneration Using the same fuel source for two forms of energy
Ex: wasted heat from a furnace can be used to produce electricity

24. Energy Conservation – saving energy by reducing use and waste
How can we do this in our lives???

26. Energy Efficient Home